Potential for New Pumped Storage Schemes in South Africa

On the South African grid, pump storage schemes offer a range of benefits. They improve grid flexibility and service peak demand, while also increasing the base load utilization level for thermal plants. Financially they potentially offer higher returns compared to alternative peak generation options that use relatively high cost fuel. The Integrated Resource Plan for South Africa currently proposes adding gas turbines and batteries to the future grid for peaking capacity and increased flexibility, with no added pump storage. This paper investigates the costs, services and contributions of pumped storage on the grid, the history of this technology and its potential future role. Within the South African context the paper aims to address the possible misconception of limited pump storage scheme site availability by providing an overview of site feasibility studies conducted in the last ten years, including estimated cost projections. Ultimately the paper argues that there is still potential for additional pumped storage on the future grid, and that further research should be done in order to analyze and better inform the energy modelling inputs and assumptions which are currently being used.